Synthesis and beta-adrenergic properties of (Z)-N-[3-(alkylamino)-2-hydroxypropylidene](aryl-methyloxy)amines: effects of the configuration around the methyloxyiminomethyl (MOIM) double bond on the biopharmacological properties of MOIM-type beta-blocking agents

The N-isopropyl- (3a-g) and N-tert-butyl-substituted (4a-g) (Z)-N-(3-(amino)-2-hydroxypropylidene)-(arylmethyloxy)amines were synthesized in order to compare their beta 1- and beta 2-adrenergic properties with those of their previously studied corresponding analogues with the E configuration (1a-g and 2a-g). Compounds 3 and 4 were tested for their affinity for beta 1-a and beta 2-adrenoceptors by radioligand binding experiments, and the compounds with the highest affinity were also assayed for their activity towards the same types of beta-adrenoceptors by functional tests on isolated preparations. The Z-methyloxyiminomethyl (Z-MOIM) compounds 3 and 4 proved to possess, on the whole, affinity (Ki) and activity (PIC50) indices similar to those of the E isomers 1 and 2, thus indicating that for the MOIM-type beta-adrenergic antagonists 1-4, the type of configuration around the MOIM double bond does not have any appreciable effect either on the affinity or on the activity towards beta-adrenoceptors. These results are rationalized on the basis of the steric and electronic analogies existing between the MOIM groups of 1-4 in the two types of configurations (E and Z).

Toward the rational development of peptidomimetic analogs of the C-terminal endothelin hexapeptide: development of a theoretical model

In an early report on the structure-activity relationship of endothelin (ET) peptides, it was reported that the C-terminal hexapeptide ET(16-21), His-Leu-Asp-Ile-Ile-Trp, is the minimum ET fragment which maintains biological activity in some, but not all the tissues responding to ETs. Subsequently, other authors described a series of analogs of this peptide, in which the His 16 residue was replaced by non-natural amino acids, characterized by bulky aromatic side chains. Among them, two well-characterized non-selective ETA/ETB antagonists were PD 142893 and PD 145065; interest in these potent ET antagonists was, however, reduced by their peptidic structure which was likely to lead to undesirable properties such as poor bioavailability and short duration of action. On the basis of these premises, our previous studies led to the development of a peptidomimetic ligand of ET receptors (compound 3), based on the replacement of the His 16 residue of ET(16-21) with an (E)-N-(benzyloxy)iminoacyl moiety; compound 3 proved to possess a certain affinity for ET receptors, albeit lower than that shown by PD 142893 and PD 145065. We report here on ETA/ETB binding affinity of compounds 4-12, designed as a new series of ET(16-21) analogs. Compounds 4 and 5 were practically devoid of any affinity; derivatives 6-12 exhibited appreciable affinity indices for ETB receptors higher than that shown by 3, even if still lower than that obtained for PD 145065. This paper also describes the development of a pharmacophoric model able to explain the ET receptor binding properties of our hexapeptide analogs compared with those of PD 142893 and PD 145065 and IRL2500, recently reported as a potent ETB selective endothelin antagonist.

Geranylgeraniol overcomes the block of cell proliferation by lovastatin in C6 glioma cells

It is well documented that 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors prevent cultured mammalian cells from progressing through the cell cycle, suggesting a critical role for a mevalonate-derived product. Recently, it has been shown that free geranylgeraniol (GG-OH) and farnesol (F-OH) can be utilized by C6 glioma cells for protein isoprenylation. The ability of GG-OH and F-OH to restore protein geranylgeranylation or farnesylation selectively has enabled us to examine the possibility that mevalonate is essential for cell proliferation because it is a precursor of farnesyl pyrophosphate or geranylgeranyl pyrophosphate, the isoprenyl donors involved in the posttranslational modification of key regulatory proteins. In this study we report that GG-OH, as well as mevalonate, overcomes the arrest of cell proliferation of C6 glioma cells treated with lovastatin, as assessed by increased cell numbers and a stimulation in [3H]thymidine incorporation. The increase in cell number and [3H]thymidine incorporation were significantly lower when F-OH was added. Under these conditions [3H]mevalonate and [3H]GG-OH are actively incorporated into a set of isoprenylated proteins in the size range of small, GTP-binding proteins (19-27 kDa) and a polypeptide with the molecular size (46 kDa) of the smaller isoform of 2 ',3'-cyclic nucleotide 3'-phosphodiesterase. Analysis of the proteins metabolically labeled by [3H]mevalonate and [3H]GG-OH reveals the presence of labeled proteins containing geranylgeranylated cysteinyl residues. Consistent with geranylgeranylated proteins playing a critical role in the entry of C6 cells into the cell cycle, a (phosphonoacetamido)oxy derivative of GG-OH, a drug previously shown to interfere with protein geranylgeranylation, prevented the increase in cell number when mevalonate or GG-OH was added to lovastatin-treated cells. These results strongly suggest that geranylgeranylated proteins are essential for progression of C6 cells into the S phase of the cell cycle and provide the first evidence that the "salvage" pathway for the utilization of the free isoprenols is physiologically significant in the CNS.

Synthesis and aldose reductase inhibitory activity of new N-(benzyloxy) glycine derivatives

This paper reports the synthesis and aldose reductase (AR) inhibitory properties of some N-(benzyloxy) glycine derivatives (compounds 2-6), structurally related to the previously described N-(aroyl)-N-(arylmethyloxy) glycines A which had proved to possess an appreciable AR inhibitory activity. In compounds 2-5, spacers of different lengths and degrees of rigidity were inserted between the phenyl ring and the carbonyl group of type A derivatives; compound 6 differs from the most active type A derivative (compound 1) in the replacement of the methoxy moiety in the para position of the benzoyl side-chain with a group with different electronic characteristics, such as the trifluoromethyl moiety. Biological results indicated that among compounds 2-5 only derivative 3, which presents a CH2CH2 spacer between the phenyl and the carbonyl moiety, proved the possess AR inhibitory properties analogous to those of 1, while all the other compounds proved to be devoid of any significant activity. Furthermore, compound 6 showed an inhibitory activity about 3 times lower than that of 1.

Ultrastructural and biochemical evidence of apoptosis induced by a novel inhibitor of protein geranylgeranylation in human MIA PaCa-2 pancreatic cancer cells

Analogs of geranylgeranyl diphosphate (GGdP) have been demonstrated to inhibit the geranylgeranylation of proteins, producing cytotoxic activity in human prostate cancer cells. A detailed study is reported on the programmed cell death in vitro of human exocrine pancreas cancer cells (MIA PaCa-2) induced by the most active compound of this series of geranylgeranylation inhibitors, the dipotassium salt of (E,E,E)[2-oxo-2-[[(3,7,11,15-tetramethyl-2, 6,10,14-hexadecatetraenyl)-oxy]amino]ethyl] phosphonic acid (BAL 9504), using transmission and scanning electron microscopy (SEM). The results show that, after 72 h of treatment with BAL 9504, 25 microM, most MIA PaCa-2 cells display the typical morphological features of apoptosis, including condensation of nuclear chromatin, dilation of endoplasmic reticulum, and fragmentation of both nucleus and cytoplasm, giving rise to small membrane-bound vesicles (apoptotic bodies); surface protrusions and blebs are well demonstrated by SEM. The electrophoresis showed the presence of various bands corresponding to fragmented DNA of 180 base pairs, or multiples of this length, thus indicating that BAL 9504 effectively induces apoptosis. The present study provides the first evidence that inhibition of protein geranylgeranylation produces apoptosis in human MIA PaCa-2 exocrine pancreas cancer cells.

[Role of echography in the diagnosis of urethral stenosis]

A recently developed ultrasonographic technique was described to evaluate the anterior urethra in 10 men suspected to have urethral stenoses. With the patient in frog leg position, during a perfusion of the urethra with saline through a catheter positioned at the beginning of the urethra, penile, transscrotal and transperineal scanning of the urethra was obtained. In all patients a diagnosis of urethral stenoses was made. After sonographic evaluation all patient underwent retrograde urethrogram and internal urethrotomy, that confirmed the diagnosis made by ultrasound. The urethral ultrasound provides valuable informations about the number, extent, position of the strictures and eventual scarring of the periurethral tissue. Urethral ultrasonography can be used as alternative imaging modality to the conventional radiological techniques.

Synthesis and antimicrobial activity of 7 beta-(S)- and 7 beta-[(R)-3-(methyleneaminoxy)-2-methylpropionamido]substituted cephalosporanic acid derivatives

Some 7-amino cephalosporanic acid derivatives substituted on the C(7) nitrogen with (S)-and (R)-3-(methyleneaminoxy)-2-methylpropionyl groups were synthesised and tested in vitro for their antimicrobial activity against Gram-positive and Gram-negative bacteria. Some of the new compounds showed a modest activity directed only against Gram-positive microorganisms.

Geranylgeranyl diphosphate-based inhibitors of post-translational geranylgeranylation of cellular proteins

A novel series of stable analogs of geranylgeranyl diphosphate (GGdP) are described in which the biologically labile diphosphate moiety of GGdP is replaced by portions that can act as stable isosters. The compounds inhibited the geranylgeranyltransferase activity in whole PC-3 prostate cancer cells, as determined by the inhibition of post-translational isoprenylation of the small GTP-binding protein p21rap 1 and the accumulation of unprocessed p21rap 1 in the cytosolic fraction. However, the compounds did not affect the farnesylation of p21ras, as shown by protein immunoprecipitation after whole cell labeling with [3 H]-(R,S)-mevalonolactone. Despite the absence of effects of post-translational processing of p21ras, these compounds proved to be cytotoxic for prostate cancer cells, with half-maximal inhibition of cell growth obtained in the range 18.5-35.1 microM. The GGdP analogs described in the this study are novel, non-peptidic inhibitors of geranylgeranylation that may be active as antitumor agents.

(E)-(methyloxyimino)acetamides as analogues of neuroleptic benzamides: synthesis and D2-dopaminergic binding affinity

Some type C (E)-(methyloxyimino)acetamides were synthesised as analogues of type A neuroleptic and antipsychotic benzamides, in which the aromatic group is substituted by a methyloxyiminomethyl moiety with the E configuration (CH2ON = CH, E-MOIMM). Type C compounds were tested for their D2-dopaminergic binding affinity in order to obtain an indication of their potential neuroleptic and antipsychotic properties. Biological results showed that only a few aryl-substituted E-MOIM derivatives possess a certain affinity for the D2-dopaminergic receptor, at least one order of magnitude lower than that of metoclopramide and sulpiride.

Synthesis and antimicrobial activity of benzo[a]dihydrocarbazole and benzotetrahydrocyclohept[1,2-b]indole derivatives

A certain number of benzodihydrocarbazoles and benzotetrahydrocycloheptindoles were synthesized and tested for their antimicrobial activity. Compounds substituted on the nitrogen of the tetracyclic systems with a dimethylaminopropyl chain showed an antibacterial activity directed almost exclusively towards Gram-positive bacteria, while their N-unsubstituted analogs were completely inactive.

(E)-(arylmethyleneaminoxy)acetamides as analogues of neuroleptic benzamides: synthesis and D2-dopaminergic binding affinity

Some type B (E)-(arylmethyleneaminoxy)acetamides were synthesised as analogues of type A neuroleptic and antipsychotic benzamides, in which the aromatic group is substituted by a (methyleneaminoxy)methyl moiety (C = NOCH2, MAOMM). Theoretical studies were performed in order to verify whether conformational analogies could exist between type A and type B compounds. Type B compounds were tested for their D2-dopaminergic binding affinity which represents a valid indication of their potential neuroleptic and antipsychotic properties. Biological results indicate that the MAOMM is not able to substitute the aromatic group effectively in the field of neuroleptic benzamides. The results are discussed in the light of the structural analogies and the differences between the MAOMM and the aryl.

Synthesis and antimicrobial activity of 7 beta-[N-(arylmethyloxyimino) acetamido]cephalosporanic acid derivatives

Some cephalosporanic acid derivatives substituted on the C(7) amino nitrogen with (arylmethyloxyimino)acetyl moieties were synthesized and tested in vitro for their antimicrobial activity against Gram positive and Gram negative bacteria. The new compounds showed a modest activity directed only against Gram positive microorganisms.

Synthesis and beta-adrenergic activity of a series of 3-(substituted-benzylideneaminoxy)propanolamine derivatives

In an attempt to change the beta-adrenergic properties of completely aliphatic 3-(methyleneaminoxy)propanolamine derivatives, from antagonist to agonist, while still retaining the beta 2-selectivity, we described, in a previous paper, the synthesis of a series of such derivatives possessing a hydroxy or methoxy group linked to the aliphatic substituent present on the oximic carbon. However, pharmacological tests indicated that these compounds maintain the competitive antagonism on beta receptors. In this paper, the synthesis and the results of functional tests on isolated preparations are reported for a new series of 3-(substituted-benzylideneaminoxy)propanolamine derivatives in which either the hydroxy or the methoxy group is linked to a phenyl ring present on the oximic carbon. The results obtained are then discussed, taking into account the conformational and reactivity properties of these compounds, determined by means of theoretical calculations.

Synthesis and adrenergic beta-blocking activity of ortho-, meta- and para-oxypropanolamino-substituted [(benzylideneamino)oxy]propanolamines

The N-isopropyl- and N-t-butyl-substituted 1-[o-(3-amino-2-hydroxypropoxy)benzylideneaminoxy]-3-amino-2-propa nols (7a,b) and their meta (8a,b) and para (9a,b) isomers, in which a single aromatic ring is substituted both by the oxypropanolaminic chain of (aryloxy)propanolaminic beta-adrenergic antagonists (AOPAs) and the [(methyleneamino)oxy]propanolaminic chain of [(methyleneamino)oxy]-propanolaminic beta-blocking drugs (MAOPAs), were synthesized and assayed for their beta-adrenergic activity by functional tests on isolated preparations. Compounds 7-9 represent a new type of molecular duplication of beta-adrenergic drugs, formally deriving from the sharing of the aromatic portions of two different pharmacophoric subunits, namely the (aryloxy)propanolaminic portion of AOPAs and the [(benzylideneamino)oxy]propanolaminic portion of aryl-substituted MAOPAs. The pharmacological results showed that the beta-blocking activity of compounds 7-9 is closely related to the way in which the two subunits are linked by the aromatic nucleus: the activity decreases on passing from the ortho-compounds (7a,b) to the meta (8a,b) and then to the para (9a,b) isomers. A comparison of this activity trend with those found for series of both beta-blocking AOPAs and aryl-substituted MAOPAs seems to indicate that compounds 7-9 can be considered more as AOPAs substituted on the phenyl ring by a [(methyleneamino)oxy]propanolaminic chain rather than as aromatic MAOPAs substituted on the same phenyl moiety by an oxypropanolaminic portion.

Synthesis, antiinflammatory activity and platelet antiaggregating activity of a new series of beta-aminoxypropionic acids

A series of beta-aminoxypropionic acids (AOPAs) had previously been designed and synthesised as analogues of antiinflammatory arylacetic acids (ArAAs) in which the Ar portion is substituted by the (methyleneaminoxy) methyl moiety (C = NOCH2, MAOMM). Most of these AOPAs had exhibited a significant antiinflammatory and antiaggregating activity. This paper reports the synthesis of a new series of beta-aminoxypropionic acids (SAOPAs) which include the saturated (methylaminoxy)methyl moiety (CHNH-OCH2, SMAOMM) in the place of the MAOMM present in AOPAs. The antiinflammatory activity of SAOPAs was evaluated by the carrageenan-induced paw edema method and the antiaggregating activity was evaluated by means of tests using arachidonic acid (AA) and adenosine diphosphate (ADP) as the aggregating agents. Two SAOPAs were evaluated for their capacity to inhibit the cyclooxygenase enzyme by measuring the malondialdehyde (MDA) produced by incubation of sodium arachidonate with platelet-rich plasma (PRP). The pharmacological results showed that the saturation of the iminic double bond led to a reduction or even the disappearance of the antiaggreganting activity, whereas it did not induce any evident changes in the antiinflammatory activity. Theoretical studies were carried out in order to compare the conformation and the molecular reactivity of SAOPAs with those of AOPAs.

Synthesis and beta-adrenergic activity of new completely aliphatic 3-(methyleneaminoxy)propanolamine derivatives

In a previous paper, it had been found that completely aliphatic 3-(methylene aminoxy)propanolamine derivatives showed a good beta-blocking adrenergic activity directed prevalently towards beta 2-tracheal receptors. In an attempt to change the beta-adrenergic properties of these compounds from antagonist to agonist, while still retaining the beta 2-selectivity, a series of new completely aliphatic 3-(methyleneaminoxy)propanolamine derivatives were designed in which either a hydroxylic or a methoxylic group was present on the aliphatic portion linked to the oximic carbon. The synthesis of the new compounds and their beta-adrenergic activity, evaluated by means of functional tests on isolated preparations, are described and discussed; the results obtained are then rationalised on the basis of their conformational and reactivity characteristics, determined by means of theoretical methods.

Synthesis, platelet anti-aggregating activity and anti-inflammatory activity of a series of beta-aminoxypropionic acids

This paper reports the platelet anti-aggregating activity induced by arachidonic acid (AA) and by adenosine-diphosphate (ADP), together with the anti-inflammatory activity evaluated by the carrageenan-induced rat paw edema method, of a series of beta-aminoxypropionic acids which were projected and synthesised as analogues of non-steroidal anti-inflammatory drugs with an arylacetic structure B, in which the aromatic group is substituted by a methyleneaminoxymethylic moiety. Some of the beta-aminoxypropionic acids were evaluated for their capacity to inhibit the cyclooxygenase enzyme by measuring the malondialdehyde (MDA) produced by incubation of sodium arachidonate with platelet-rich plasma (PRP).